Single-primer nucleic acid amplification methods
First Claim
1. A method of synthesizing multiple copies of a target sequence, said method comprising the steps of:
- (A) treating a target nucleic acid comprising an RNA target sequence with;
(1) a priming oligonucleotide which hybridizes to the 3′
-end of said target sequence such that a primer extension reaction can be initiated therefrom, wherein at least one of the following conditions is satisfied;
(a) said priming oligonucleotide does not comprise RNA; and
(b) said priming oligonucleotide has a cap hybridized to a 3′
-end thereof prior to hybridizing to said target sequence, said cap comprising a base region which is complementary to at least 3 nucleotides at the 3′
-end of said priming oligonucleotide, wherein the 5′
-terminal base of said cap is complementary to the 3′
-terminal base of said priming oligonucleotide, and wherein said cap is modified to prevent the initiation of DNA synthesis therefrom; and
(2) a binding molecule which binds to said target nucleic acid adjacent to or near the 5′
-end of said target sequence;
(B) extending said priming oligonucleotide in a primer extension reaction with a DNA polymerase to give a DNA primer extension product complementary to said target sequence, said DNA primer extension product having a 3′
-end which is determined by said binding molecule and which is complementary to the 5′
-end of said target sequence;
(C) separating said DNA primer extension product from said target sequence using an enzyme which selectively degrades said target sequence;
(D) treating said DNA primer extension product with a promoter oligonucleotide comprising first and second regions, said first region hybridizing to a 3′
-region of said DNA primer extension product to form a promoter oligonucleotide;
DNA primer extension product hybrid, and said second region being a promoter for an RNA polymerase and situated 5′
to said first region, wherein any oligonucleotide provided in said method which comprises a promoter for an RNA polymerase is modified to prevent the initiation of DNA synthesis therefrom;
(E) extending the 3′
-end of said DNA primer extension product in said promoter oligonucleotide;
DNA primer extension product hybrid to add a sequence complementary to said second region of said promoter oligonucleotide; and
(F) transcribing from said promoter oligonucleotide;
DNA primer extension product hybrid multiple RNA products complementary to said DNA primer extension product using an RNA polymerase which recognizes said promoter and initiates transcription therefrom, wherein the base sequences of said RNA products are substantially identical to the base sequence of said target sequence.
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Abstract
The present invention is directed to novel methods of synthesizing multiple copies of a target nucleic acid sequence which are autocatalytic (i.e., able to cycle automatically without the need to modify reaction conditions such as temperature, pH, or ionic strength and using the product of one cycle in the next one). In particular, the present invention discloses a method of nucleic acid amplification which is robust and efficient, while reducing the appearance of side-products. The method uses only one primer, the “priming oligonucleotide,” a promoter oligonucleotide modified to prevent polymerase extension from its 3′-terminus and, optionally, a means for terminating a primer extension reaction, to amplify RNA or DNA molecules in vitro, while reducing or substantially eliminating the formation of side-products. The method of the present invention minimizes or substantially eliminates the emergence of side-products, thus providing a high level of specificity. Furthermore, the appearance of side-products can complicate the analysis of the amplification reaction by various molecular detection techniques. The present invention minimizes or substantially eliminates this problem, thus providing an enhanced level of sensitivity.
100 Citations
121 Claims
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1. A method of synthesizing multiple copies of a target sequence, said method comprising the steps of:
-
(A) treating a target nucleic acid comprising an RNA target sequence with; (1) a priming oligonucleotide which hybridizes to the 3′
-end of said target sequence such that a primer extension reaction can be initiated therefrom, wherein at least one of the following conditions is satisfied;
(a) said priming oligonucleotide does not comprise RNA; and
(b) said priming oligonucleotide has a cap hybridized to a 3′
-end thereof prior to hybridizing to said target sequence, said cap comprising a base region which is complementary to at least 3 nucleotides at the 3′
-end of said priming oligonucleotide, wherein the 5′
-terminal base of said cap is complementary to the 3′
-terminal base of said priming oligonucleotide, and wherein said cap is modified to prevent the initiation of DNA synthesis therefrom; and(2) a binding molecule which binds to said target nucleic acid adjacent to or near the 5′
-end of said target sequence;(B) extending said priming oligonucleotide in a primer extension reaction with a DNA polymerase to give a DNA primer extension product complementary to said target sequence, said DNA primer extension product having a 3′
-end which is determined by said binding molecule and which is complementary to the 5′
-end of said target sequence;(C) separating said DNA primer extension product from said target sequence using an enzyme which selectively degrades said target sequence; (D) treating said DNA primer extension product with a promoter oligonucleotide comprising first and second regions, said first region hybridizing to a 3′
-region of said DNA primer extension product to form a promoter oligonucleotide;
DNA primer extension product hybrid, and said second region being a promoter for an RNA polymerase and situated 5′
to said first region, wherein any oligonucleotide provided in said method which comprises a promoter for an RNA polymerase is modified to prevent the initiation of DNA synthesis therefrom;(E) extending the 3′
-end of said DNA primer extension product in said promoter oligonucleotide;
DNA primer extension product hybrid to add a sequence complementary to said second region of said promoter oligonucleotide; and(F) transcribing from said promoter oligonucleotide;
DNA primer extension product hybrid multiple RNA products complementary to said DNA primer extension product using an RNA polymerase which recognizes said promoter and initiates transcription therefrom, wherein the base sequences of said RNA products are substantially identical to the base sequence of said target sequence. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46)
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47. A method of synthesizing multiple copies of a target sequence, said method comprising the steps of:
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(A) treating a target nucleic acid comprising an RNA target sequence with a priming oligonucleotide which hybridizes to the 3′
-end of said target sequence, such that a primer extension reaction can be initiated therefrom;(B) extending said priming oligonucleotide in a primer extension reaction with a DNA polymerase to give a first DNA primer extension product having an undefined 3 ′
-end and comprising a base region complementary to said target sequence;(C) separating said first DNA primer extension product from said target nucleic acid using an enzyme which selectively degrades that portion of said target nucleic acid which is complementary to said first DNA primer extension product; (D) treating said first DNA primer extension product with a promoter oligonucleotide comprising first and second regions, said first region hybridizing to a 3′
-region of said first DNA primer extension product to form a promoter oligonucleotide;
first DNA primer extension product hybrid, and said second region being a promoter for an RNA polymerase and situated 5′
to said first region, wherein any oligonucleotide provided in said method which comprises a promoter for an RNA polymerase is modified to prevent the initiation of DNA synthesis therefrom, and wherein said first DNA primer extension product is not extended to form a double-stranded promoter comprising said promoter; and(E) transcribing from said promoter oligonucleotide;
first DNA primer extension product hybrid multiple first RNA products complementary to at least a portion of said first DNA primer extension product using an RNA polymerase which recognizes said promoter and initiates transcription therefrom, wherein the base sequences of said first RNA products are substantially identical to the base sequence of said target sequence. - View Dependent Claims (48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84)
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85. A method of synthesizing multiple copies of a target sequence, said method comprising the steps of:
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(A) treating a target nucleic acid comprising a DNA target sequence with a promoter oligonucleotide comprising first and second regions, said first region hybridizing to the 3′
-end of said target sequence to form a promoter oligonucleotide;
target nucleic acid hybrid, and said second region being a promoter for an RNA polymerase and situated 5′
to said first region, wherein any oligonucleotide provided in said method which comprises a promoter for an RNA polymerase is modified to prevent the initiation of DNA synthesis therefrom, and wherein said target nucleic acid is not extended to form a double-stranded promoter comprising said promoter;(B) transcribing from said promoter oligonucleotide;
target nucleic acid hybrid multiple first RNA products comprising a base region complementary to said target sequence using an RNA polymerase which recognizes said promoter and initiates transcription therefrom;(C) treating one of said first RNA products with a priming oligonucleotide which hybridizes to a 3′
-region of said first RNA product, such that a primer extension reaction can be initiated therefrom;(D) extending said priming oligonucleotide in a primer extension reaction with a DNA polymerase to give a DNA primer extension product complementary to at least a portion of said first RNA product, said DNA primer extension product having a 3′
-end which is complementary to the 5′
-end of said first RNA product;(E) separating said DNA primer extension product from said first RNA product using an enzyme which selectively degrades said first RNA product; (F) treating said DNA primer extension product with said promoter oligonucleotide to form a promoter oligonucleotide;
DNA primer extension product hybrid; and(G) transcribing from said promoter oligonucleotide;
DNA primer extension product hybrid multiple second RNA products complementary to said DNA primer extension product using said RNA polymerase, wherein the base sequences of said second RNA products are substantially complementary to the base sequence of said target sequence. - View Dependent Claims (86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 115, 116, 117, 118, 119, 120, 121)
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Specification